1. Field of the Invention
This invention relates generally to detection of hydrogen gas leaking from a pressure regulator and, more particularly, to a method and system for detecting hydrogen leaking from a pressure regulator in a hydrogen storage system for a fuel cell which connects the atmospheric reference port of the pressure regulator to an existing open-environment hydrogen sensor, thus providing both the atmospheric reference pressure signal for the regulator and a means of directly detecting any hydrogen gas leakage from the regulator.
2. Discussion of the Related Art
Fuel cell vehicles are expected to rapidly increase in popularity in the near future in the automotive marketplace. Fuel cell vehicles offer several desirable features, such as virtually pollution-free emissions, and avoiding vehicle usage of petroleum fuels. A key component of fuel cell vehicles is the hydrogen storage system, which stores the hydrogen used as a fuel by most fuel cell vehicles. Hydrogen storage systems typically consist of one or more interconnected pressure vessels for storing gaseous hydrogen, along with numerous valves, gauges, and fittings necessary for operation of the hydrogen storage system. Maximizing vehicle driving range, while fitting within packaging constraints and meeting regulatory requirements, is a key consideration in the design of hydrogen storage systems for fuel cell vehicles.
Fuel cells require a reliable source of hydrogen gas at a prescribed pressure. One or more pressure regulators are used to reduce the hydrogen gas from the high pressure at which it is stored in the vessels to the lower prescribed pressure required by the fuel cell. Although rare, it is possible that a pressure regulator could develop a leak which allows hydrogen gas to flow through an unintended path into the environment.
Existing hydrogen sensors in the exhaust stream may not be able to reliably detect the presence of unintended hydrogen, due to dilution by the exhaust flow and for other reasons. There is a need for a reliable means of detecting hydrogen gas which may leak from a pressure regulator in a hydrogen storage system.